Paving machines may be used in the laying of bituminous roadway mat. A typical paving machine employs a screed assembly (sometimes referred to as a floating screed) for spreading and compressing a bituminous material to form a smooth surfaced roadway mat. The screed assembly may include, as an accessory, an extendable section for attachment to an end of a fixed section of the screed assembly, in a rear or forward mounted arrangement. The extendable section may include an adjustable end gate that allows an operator to adjust an effective width of the screed assembly, for forming roadway mats that comply with wider tolerances. The extendable section may also facilitate overwidth paving of the roadway mats to accommodate various roadway features (e.g., driveway entrances, tie-ins, and/or the like).
The extendable and fixed sections of the screed assembly may include vibrating and/or tamper components for imparting vibrating and/or tamper functionality, which improve the screed assembly's compactive abilities. In this regard, and, in an effort to improve the uniformity of roadway mat surfaces, it may be desirable for the vibrating and/or tamper functionality imparted by the fixed sections to closely match the vibrating and/or tamper functionality imparted by the extendable sections. Generally, this has proven difficult to achieve, as the addition of complex control components, to the screed assembly, are required to provide similar and/or consistent vibrating and/or tamper functionality across the extendable and fixed sections.
Further difficulties may arise in connection with transmitting power to the extendable sections. For example, long sections of hosing are currently being used to transmit power from a base of the fixed screed, located at a center of the screed assembly, to the extendable sections, located at or near the ends of the screed assembly. The long sections of hosing may be cumbersome, difficult to store, and/or difficult to assemble.
One attempt to address one such issue, and to provide improved control over operation of an extendable section, is disclosed in U.S. Pat. No. 8,979,425, that issued to Caterpillar Paving Products Inc., on Mar. 17, 2015 (“the '425 patent”). Per the '425 patent, an electro-hydraulic system is provided to extend or retract the extendable screed relative to the main screed, and includes an on/off switch to move and stop the extendable screed as a desired width of paving. However, greater control is required to move and vary the width of paving using the extendable screed. The '425 patent discloses providing a screed assembly that includes a control system for the extendable screed. The control system includes a first input device configured to set a speed limit for the extendable screed, a second input device configured to vary a speed of the extendable section, within the speed limit, and a third input device configured to govern a relationship between a speed of the extendable screed and a relative position of the second input device.
While the control system disclosed by the '425 patent addresses a method of improving control over a speed and/or movement of an extendable screed, a need exists for improved screed assemblies in order to address problems relating to routing power to the extendable screed and/or problems relating to inconsistent tamper and/or vibrating functionality provided by the main screed and the screed extension, and/or other problems in the art.